Many companies and other organizations operate computer networks that interconnect numerous computing systems to support their operations, such as with the computing systems being co-located (e.g., as part of a local network) or instead located in multiple distinct geographical locations (e.g., connected via one or more private or public intermediate networks). For example, data centers housing significant numbers of interconnected computing systems have become commonplace; there are private data centers that are operated by and on behalf of a single organization, and public data centers that are operated by entities as businesses to provide computing resources to customers. Some public data center operators provide network access, power, and secure installation facilities for hardware owned by various customers, while other public data center operators provide “full service” facilities that also include hardware resources made available for use by their customers. As the scale and scope of typical data centers has increased, the tasks of provisioning, administering, and managing the physical computing resources have become increasingly complicated.
The advent of virtualization technologies has provided benefits with respect to managing large-scale computing resources for many customers with diverse needs, allowing various computing resources to be efficiently and securely shared by multiple customers. For example, virtualization technologies may allow a single physical computing machine to be shared among multiple users by providing each user with one or more computer instances hosted by the single physical computing machine, with each such virtual machine being a software simulation acting as a distinct logical computing system that provides users with an experience as if they were the sole operators and administrators of a given hardware computing resource, while also providing application isolation and security among the various virtual machines. Furthermore, some virtualization technologies are capable of providing virtual resources that span two or more physical resources, such as a single virtual machine with multiple virtual processors that spans multiple distinct physical computing systems.
Operators of networks that enable clients to use hundreds or thousands of virtualized resources within a given data center, or spread over multiple data centers, often set up interconnect topologies that offer multiple parallel physical network paths between a given pair of virtualized resources. However, many conventional approaches to networking may end up underutilizing the bandwidth available for any given high-volume data transfer, e.g., by using only a small subset of the parallel paths available. As a result of the lack of balance in the network traffic, application performance may suffer in at least some cases, and the return on the operator's investment in the high-bandwidth interconnect infrastructure may be less than satisfactory.